Referring to FIG. 1 (prior art), the most common way of removing surface asperities after sputtering involves a standard cleaning process 100 that utilizes buffing tape for cleaning post-sputter flat media disks. After sputtering (step 110), the disks are coated with a lubricant (step 120), and then buffed with the tape in a dry process environment (step 130). This type of process is the current post-sputter cleaning method used for most conventional flat media disks.
For discrete track media disks, it may be difficult to implement the type of buffing process described above because of the nano-imprinting process that typically follows. In most cases, the complete removal of the lubricant must be achieved or the photoresist material employed in the succeeding step will not securely adhere to the disks. The weak adhesion strength frequently causes the photoresist material to peel off during the subsequent stamping process, thereby resulting in a fouled stamper template.
Referring to FIG. 2 (prior art), another conventional process 200 is illustrated for cleaning post-sputter discrete track media disks prior to nano-imprint lithography. In particular, after sputtering (step 210), the process comprises an ultrasonic bath or soak (step 220), a scrubbing station for performing one or more scrubbing steps 230, 240, a rinse step 250 and a drying step 260. While this method is sufficient for getting rid of loose particles, it is not adequate for removing protrusions in the surface topography. In some cases, the use of different soaking agents, sponge materials, and even lengthening the brushing cycle can help further reduce the incidence of loose particles. However, such modifications tend to have a negligible effect on stubborn surface imperfections that can inflict permanent damage on the stamper.
Another conventional process is a widely used texturing process that adds uniform roughness to the surfaces of disks prior to sputtering as opposed to after sputtering. This process employs a tape material with an alumina or diamond slurry, or a fixed-abrasive tape in combination with a lubricant.